Luc Brouillet, John C. Semple, Geraldine A. Allen, Kenton L. Chambers, Scott D. Sundberg+ in Flora of North America (vol. 20)
Plants (10-)60-200 cm. Stems usually simple, sometimes branched proximally. Heads 15-120, in open, diffuse arrays, secund on primary branches longer than peduncles. Involucres (5.2-)6-6.9 mm. Phyllaries 25-45(-62), subulate to lanceolate, narrow, green zones narrowly lanceolate. Ray florets 17-30(-45) in 1 series; laminae lavender to blue, (3.5-)4.5-7 × 0.9-1.3 mm, longer than pappi, drying in 3-5 coils (apices shallowly lobed). Disc florets (20-)33-50; corollas 3.7-4.5(-5) mm. Cypselae (1.3-)1.7-2.5(-2.9) mm; pappi (3-)3.5-4.6 mm. 2n = 10. Flowering Jul-Nov(-Feb). Marshy habitats, often weedy, roadsides, lawns, waste places; 0-1500 m; Ala., Ark., Kans., La., Miss., Nebr., N.Mex., Okla., Tenn., Tex.; Mexico (Chihuahua, Coahuila, Tamaulipas).
FNA 2006, Jepson 1993, Kearney and Peebles 1969, McDougall 1973
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Herbaceous annuals to biennials, to 200 cm tall, stems spreading, at least above the middle, sometimes purple, glabrous to glabrate, sometimes with hairs in the axils, the plants with long rhizomes. Leaves: Alternate, thin, basal leaves ovate to oblanceolate, to 9 cm long and 1.5 cm wide, margins entire to minutely toothed, the faces sparsely ciliate, blades petiolate on winged petioles, cauline leaves subpetiolate or sessile, narrowly lanceolate, to 10 cm long and 1 cm wide, margins subentire, entire, or serrulate. Flowers: Heads radiate, rays lavender to violet or blue, 4-7 mm long, drying in coils, 17-30, occurring in a single series, disk flowers yellow, 35-50, involucres cylindric to turbinate, graduated, 6-7 mm high, phyllaries 25-45 in 3-5 series, lanceolate to awl-shaped, unequal, often purple-tinged, margins entire, heads in groups of 1-many, borne on branch tips in open, paniculiform arrays. Fruits: Achenes light brown to purple, narrowly obovoid to fusiform, sometimes compressed, 1.5-3 mm long, 5-nerved, the faces sparsely stiff hairs. Pappus of white, sub-equal capillary bristles, 3.5-4.5 mm long. Ecology: Found in marshy habitats, and disturbed areas, roadsides, and lawns, from 0-5,000 ft (0-1524 m); flowering July-November. Distribution: Alanta, Arkansas, Kansas, Louisiana, Mississippi, Nebraska, New Mexico, Oklahoma, Tennessee, Texas; Mexico Notes: There is some uncertainty as to wether this is the correct name; Tropicos correlates S. subulatum var. ligulatum to this taxa but does not provide certainty, however, both Jepson and FNA also use S. subulatum var. ligulatum. Good identifiers for this variety are the lavender to violet or blue ray flowers, which occur only in a single series. Ethnobotany: A decoction of the roots was used as a wash for headaches, and mashed roots were applied to the tooth for a toothache. Etymology: Symphyotrichum comes from Greek symphysis for borne together and trichnos for hair, while subulatum means awl-shaped and ligulatum refers to the ligulate flowers. Synonyms: Symphyotrichum divaricatum, several others, see Tropicos Editor: LCrumbacher 2011